Two new species of Sinella from Guangdong Province, China (Collembola: Entomobryidae)

ZooKeys él I: | | 0 (20 | 6) A peer-reviewed open-access journal
doi: 10.3897/zookeys.61 1.9025 RESEARCH ARTICLE #ZooKey S

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Two new species of Sinella from Guangdong Province,
China (Collembola: Entomobryidae)

Guo-Liang Xu', Wei-Yu Chen?

I School of Geographical Sciences, Guangzhou University, Guangzhou 510006, PR. China 2 Nanjing Plant
Protection Station, No 169 Hanzhongmen Road, Nanjing 210036, P R. China

Corresponding author: Guo-Liang Xu (xugl@gzhu.edu.cn)

Academic editor: L. Deharveng | Received 27 April 2016 | Accepted 6 August 2016 | Published 15 August 2016
Attp://zoobank.org/1 BBF7A67-5A46-4806-AEGE-D84F719A4C51

Citation: Xu G-L, Chen W-Y (2016) Two new species of Sinella from Guangdong Province, China (Collembola:
Entomobryidae). ZooKeys 611: 1-10. doi: 10.3897/zookeys.611.9025

Abstract

Two new blind species of Sinella are described from Guangdong Province, China. Sinella colubra sp. n.
possesses minute smooth postlabial chaetae, long mucronal spine, and 4+4(5) lateral mac on Abd. IV, and
can be distinguished from two closely related species by the postlabial chaetae and the dorsal macrochae-
totaxy. Sinella zhangi sp. n. is also described and can be diagnosed by having minute labial chaeta r and
postlabial chaetae X and X,, 5+5 mac on Abd. I, 4+4 central mac on Abd. II, and 4+4 central and 5+5
lateral mac on Abd. IV.

Keywords
Blind species, chaetotaxy, springtail, Sinella colubra sp. n., Sinella zhangi sp. n., South China

Copyright Guo-Liang Xu andWei-Yu Chen. This is an open access article distributed under the terms of the Creative Commons Attribution License
(CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

2 Guo-Liang Xu & Wei-Yu Chen / ZooKeys 611: I-10 (2016)

Introduction

The genus Sinella Brook, 1882 is distributed worldwide and is very abundant in Chi-
na. Deharveng (1990), Chen and Christiansen (1993) and Zhang et al. (2009, 2011)
made significant contributions to the modern taxonomy of the genus. Members of the
genus have 4-segmented antennae, reduced eye number (0-G on each side), pigment
reduced or absent, polymacrochaetotic chaetotaxy, bidentate mucro, and no dental
spines and scales. So far, 39 species, including 14 blind ones, have been recorded from
China. Among them, only two eyed species have been recorded from Guangdong
Province: Sinella curviseta Brook, 1882 and Sinella longisensilla Zhang, 2013. In this
study, two new blind species are described from Guangdong.

Materials and methods

Specimens were cleared in Nesbitt’s fluid (Krantz 1978), mounted under a coverslip
in Hoyer’s solution, and observed using a Nikon E80i microscope. The labial chaetae
terminology follows Gisin’s system (1967). The dorsal and ventral chaetotaxy of head
are described after Chen and Christiansen (1993), completed for the anterior part of
head after Jordana and Baquero (2005) and Soto-Adames (2008). Dorsal body chaetae
are designated following Szeptycki (1979) and Zhang et al. (2011). The number of
macrochaetae is given by half-tergite in the descriptions (left side of tergites drawn
in figures). Tergal S-chaetotaxic formula follows Zhang and Deharveng (2015). All
descriptions are based on fully developed adults if not otherwise mentioned. Symbols
representing chaetal elements used in the figures are as follows: large circle, macro-
chaeta; small circle, mesochaeta; cross, bothriotrichum; circle with a slash, pseudopore;
dotted circle, chaetae present or absent. All materials are deposited in the collections
of the Department of Entomology, College of Plant Protection, Nanjing Agricultural
University (NJAU), P. R. China.

Abbreviations:

Th. thoracic segment;

Abd. abdominal segment;

Ant. antennal segment;

mac —_ macrochaeta/ae;

mic microchaeta/ae;

mes mesochaeta/ae

ms S-microchaeta/ae;

sens ordinary tergal S-chaeta/ae.

Two new species of Sinella from Guangdong Province, China... 3
Taxonomy

Sinella colubra sp. n.
http://zoobank.org/543604B9-A3BA-4FA9-ADC0-A506FCC99B04
Figs 1-16, Table 1

Type material. Holotype: 3 on slide, China, Guangdong Province, Huizhou City,
Longmen County, Nankunshan Natural Reserve, 23°38'4.01”N, 113°51'15.25”E, al-
titude 497 m, 24 August 2010, Z-X Pan and Y-T Ma leg. (# $4143). Paratypes: CS and
3 29 on slides and 3 in alcohol, same data as holotype.

Other material. 9 on slide, China, Guangdong Province, Nanling National Nat-
ural Reserve, 24°55'42.6"N, 113°0'58.3"E, altitude 1026 m, 22 July 2010, F Zhang
and Z-H Li leg. (# C9640).

Diagnosis. No eyes. Long smooth straight chaetae present on antennae. Clypeal
chaetae eight and median three much smaller. Labial chaetae as mrel,|,. Postlabial
chaetae X and X,_, minute. “Smooth” inner differentiated tibiotarsal chaetae present.
Manubrium without smooth chaetae. Mucronal spine long, with tip nearly reaching
apical tooth. Abd. I with 6+6 mac. Abd. II with 3+3 central mac. Abd. IV with 7+7
central and 4+4 lateral mac.

Description. Body length up to 1.50 mm. Body pale in alcohol.

Antenna 1.63-1.93 times as long as cephalic diagonal. Antennal segments ratio as
I: If: Il: IV = 1: 1.77-2.00 : 1.64-1.74 : 2.57-2.91. Smooth spiny mic at base of
antennae: three dorsal, three ventral on Ant. I; one internal, one external and two ven-
tral on Ant. II. Ant. II distally with one (rarely two) rod-like sens. Ant. III organ with
two slightly expanded internal sens. Ant. IV with a knobbed subapical organ. Ant. I.
with 2-4 ventral long smooth straight chaetae.

Eyes absent in all specimens. Prelabral and labral chaetae 4/ 5, 5, 4, all smooth;
labral intrusion U-shaped (Fig. 1). Clypeal chaetae eight in number, including three
small median chaetae (Fig. 2). Dorsal cephalic chaetotaxy with four antennal (An),
three median (M) and eight sutural (S) mac; Gr. II with 3(4) mac (Fig. 3). Mandibles
with 4/5 (left/right) teeth. Subapical chaeta of maxillary outer lobe slightly thicker
than apical one; three smooth sublobal hairs on maxillary outer lobe. Lateral process
of labial palp slightly thicker than normal chaetae, with tip extending beyond apex of
labial papilla (Fig. 4). Labial chaetae as mrel L, all smooth, r/m=0.67-0.79; chaetae
X and X,_, minute; chaeta X, rarely absent; H, , smooth. Cephalic groove with 9(8)
chaetae, four of them smooth and others ciliate (Fig. 5).

Trochanteral organ with 17-19 smooth spiny chaetae; 11-12 in arms and 5-7
internal (Fig. 6). Partial inner differentiated tibiotarsal chaetae “smooth” with cilia-
tions closely appressed to axis (Chen and Christiansen 1993). Tibiotarsi distally with
ten chaetae in a whorl. Unguis with three inner, one outer, and two lateral teeth; two
paired teeth unequal, outer one large. Unguiculus with a large outer tooth. Tenent

4 Guo-Liang Xu & Wei-Yu Chen / ZooKeys 611: 1-10 (2016)

Figures 1-12. Sinella colubra sp. n. | labrum 2 clypeal chaetae 3 dorsal cephalic chaetotaxy 4 lateral
process and labial papilla E 5 chaetae on the ventral side of head 6 trochanteral organ 7 hind claw 8
anterior face of ventral tube 9 ventral face and lateral flap of ventral tube 10 distal part of anterior face of

manubrium I 1 manubrial plaque 12 mucro.

Two new species of Sinella from Guangdong Province, China ... 5

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Figures | 3-16. Tergal chaetotaxy of Sinella colubra sp. n. 13 thorax 14 Abd. I-HI 15 Abd. IV 16 Abd. V.

hairs of all legs pointed but clavate in one male specimen (Fig. 7). Abd. IV 3.72-4.60
times as long as Abd. III along dorsal midline. Ventral tube anteriorly with 6-7 ciliate
chaetae on each side, two of them much larger than others (Fig. 8); posteriorly with
about 13 chaetae, most of them small and weakly ciliate; each lateral flap with two
ciliate and six smooth chaetae (Fig. 9). Male genital plate not clearly seen. Manubrium
dorsally without smooth chaetae; ventrally with 5+5 distal ciliate chaetae (Fig. 10).
Manubrial plaque with 2+2(1) pseudopores and 3+3 ciliate chaetae (Fig. 11). Distal
smooth part of dens 1.08—1.57 as long as mucro. Mucro bidentate with apical tooth
larger; basal spine long, with tip nearly reaching apical tooth (Fig. 12).

Th. II with three medio-medial mac (m1, m2, m2i), three medio-lateral mac (m4,
m4i, m4p), 14-18 posterior mac, one ms and two sens; ms interior to sens al. ‘Th. III
with 29-32 mac and two lateral sens; a6i, p5, p6, m6, mG6i, m6p, mGe and m6ai2 pre-

6 Guo-Liang Xu & Wei-Yu Chen / ZooKeys 611: 1-10 (2016)

Table |. Comparison among S. colubra sp. n., S. insolens and S. sineocula. Rare character states are noted

and placed in parentheses.

Characters S. colubra sp. n. S. insolens S. sineocula

Mac in Gr. II on dorsal head 3(4) usually 4—5(6-8) usually 5—6(4)
Labial chaeta M1s absent present absent
Postlabial chaetae X and Day smooth, minute cliate, large ciliate, large
Mac m5i on Th. II absent present absent
Mac on Abd. I 6+6 7(6)+7(6) 7(6)+7(6)
Central mac on Abd. II 3+3 4+4 343
Lateral mac on Abd. IV 4(5)+4(5) 6+6 6+6

sent as mac; mac m5i absent (Fig. 13). Abd. I with six mac (a3, m2—4, m2i, m4p), one
ms and one sens; sens interior to ms. Abd. II with three central mac (m3, m3e, m3ep),
one lateral mac (m5) and two sens. Abd. III with one central mac (m3), three lateral
mac (am6, pm6, p6) and two sens; ms absent (Fig. 14). Abd. IV with seven central mac
(I, M, A5-6, B4—6), four (rarely five) lateral mac (D3, E24), and at least 17 sens (Fig.
15). Abd.V with three sens (Fig. 16).

Etymology. Named after the snake Bungarus multicinctus Blyth found in the sam-
pling site.

Ecology. In soil of bamboo forest, near termitarium.

Remarks. Sinella colubra sp. n. is most similar to Sinella insolens Chen & Chris-
tiansen, 1993 and Sinella sineocula Chen & Christiansen, 1993 in morphology of un-
guis and unguiculus, long mucronal spine, absence of smooth chaetae on manubrium,
medial and posterior mac on Th. II, 1+1 central and 3+3 lateral mac on Abd. HI, and
7+7 central mac on Abd. IV. It differs from them in 3+3(4) cephalic mac on Gtr. II,
absence of labial chaeta M1s, minute postlabial chaetae X and ae absence of mac
m5i on Th. III, 6+6 (a2 as mes) mac on Abd. I, absence of mac m3ei on Abd. II, and
4+4(5) lateral mac on Abd. IV.

Sinella zhangi sp. n.
http://zoobank.org/E8161EA4-8F9E-4C9C-8A90-CICFEBIE8A0 1
Figs 17-27

Type material. Holotype: ¢ on slide, China, Guangdong Province, He Mountain,
in soil of secondary eucalypt forest, 22 October 2012, Guoliang Xu leg. (# Xu-2012).
Paratypes: 1 2 on slide and 1 juvenile in alcohol, same data as holotype.

Diagnosis. No eyes. Long smooth straight chaetae absent on antennae. Labial chae-
ta r and postlabial chaetae X and X, minute. “Smooth” inner differentiated tibiotarsal
chaetae present. Tenent hairs clavate. Manubrium without smooth chaetae. Mucronal
spine short, with tip reaching subapical tooth. Chaeta p5 as mac on Th. I. Abd. I with
5+5 mac. Abd. II with 4+4 central mac. Abd. IV with 4+4 central and 5+5 lateral mac.

Two new species of Sinella from Guangdong Province, China... 7

Wy HWA yin ny

Figures | 7-25. Sinella zhangi sp. n. 17 dorsal cephalic chaetotaxy 18 lateral process and labial papilla E
19 chaetae on the ventral side of head 20 hind claw 21 lateral flap of ventral tube 22 manubrial plaque
23 mucro 24 thoracic chaetotaxy 25 chaetotaxy of Abd. I-III.

8 Guo-Liang Xu & Wei-Yu Chen / ZooKeys 611: 1-10 (2016)

Oo

Figures 26-27. Tergal chaetotaxy of Sinella zhangi sp. n. 26 Abd. IV 27 Abd. V.

Description. Body length up to 1.32 mm. Body pale in alcohol.

Antenna 2.04 times as long as cephalic diagonal. Antennal segments ratio as I : II
> TIT: TV = 1: 1.71: 1.86: 2.71. Smooth spiny mic at base of antennae three dorsal,
three ventral on Ant. I: one internal, one external and one ventral on Ant. IJ. Ant. II
distally with one rod-like S-chaeta. Two internal sens of Ant. III organ rod-like. Long
smooth straight chaetae absent on antennae.

Eyes absent in all specimens. Prelabral and labral chaetae 4/ 5, 5, 4, all smooth;
three chaetae of first row longer than lateral chaetae. Clypeal chaetae not clearly seen.
Dorsal cephalic chaetotaxy with four antennal, three median (M) and eight sutural (S)
mac; Gr. II with four mac (Fig. 17). Mandibles with 4/5 (left/right) teeth. Subapical
chaeta of maxillary outer lobe subequal to apical chaeta; three smooth sublobal hairs
on maxillary outer lobe. Lateral process of labial palp thicker than normal chaetae,

Ite tall

12?
smooth, r/m=0.20; chaetae X and X, smooth, minute; chaetae Da absent; H,, H, and

H, ciliate. Cephalic groove with eight chaetae, two smooth and others ciliate (Fig. 19).

with tip extending beyond apex of labial papilla (Fig. 18). Labial chaetae as mrel

Trochanteral organ with nine smooth spiny chaetae; five in arms and four internal.
Some inner differentiated tibiotarsal chaetae “smooth” with ciliations closely appressed
to axis. Tibiotarsi distally with ten chaetae in a whorl. Unguis with three inner teeth;
two paired teeth unequal, outer one larger. Unguiculus with a large outer tooth. Tenent
hairs clavate (Fig. 20). Abd. IV 3.42 times as long as Abd. III along dorsal midline.

Ventral tube anteriorly with seven ciliate chaetae; two of them much larger than oth-

Two new species of Sinella from Guangdong Province, China ... 9

ers; posteriorly not clearly seen; each lateral flap with seven smooth and one ciliate
chaetae (Fig. 21). Manubrium without smooth chaetae. Manubrial plaque with 2+2
pseudopores and 3+3 ciliate chaetae (Fig. 22). Distal smooth part of dens 1.72 times
as long as mucro. Mucro bidentate with apical tooth longer than subapical tooth; basal
spine short, reaching tip of subapical tooth (Fig. 23).

Th. II with three medio-medial mac (m1, m2, m2i), three medio-lateral mac (m4,
m4i, m4p), 19 posterior mac, one ms and two sens; ms interior to sens al. Th. II with
30 mac and two lateral sens (Fig. 24). Abd. I with five mac (m2—4, m2i, m4p), one ms
and one sens; sens interior to ms. Abd. II with four central mac (a2, m3, m3e, m3ep),
one lateral mac (m5) and two sens. Abd. III with one central mac (m3), three lateral
mac (am6, pm6, p6) and two sens; ms absent (Fig. 25). Abd. [TV with four central mac
(I, M, B5, AG), five lateral mac (E2—4, E2p, F1), and at least 11 sens; as and ps shorter
than others (Fig. 26). Abd.V with three sens; chaetae m2, m3, m5, a6, pl, p3—5 and
ap6 present as mac (Fig. 27).

Etymology. Named after the Chinese collembologist Dr. Feng ZHANG, who has
made great contributions to the taxonomy of Sinella.

Ecology. In decomposing leaves along the roads.

Remarks. Sinella zhangi sp. n. is most similar to Sinella quadriseta Zhang, Bedos
& Deharveng, 2014 in absence of eyes, tip of lateral process of labial palp beyond
apex of labial papilla, morphology of unguis and unguiculus, and mucronal spine,
but differs from it in smooth, minute labial and postlabial chaetae r, X and X ‘3 clavate
tenent hairs, “smooth” inner differentiated tibiotarsal chaetae, 4+4 mac in Gr. II on
dorsal head, absence of mac m2, m2i, m4i and m4p on ‘Th. I, 5+5 mac on Abd. I
(m4p present), and 4+4 central mac on Abd. II (m3ep present). It is also similar to
Chinese species Sinella affluens Chen & Christiansen, 1993 in 4+4 mac on dorsal head,
“smooth” inner differentiated tibiotarsal chaetae, clavate tenent hairs, number of teeth
on unguis and unguiculus, minute postlabial chaetae X and X,, 2+2 pseudopores and
3+3 ciliate chaetae on manubrial plaque, medial mac on ‘Th. II, 1+1 central mac on
Abd. II, and 4+4 central mac on Abd. IV, but differs from the latter in absence of eyes,
short mucronal spine, minute labial chaeta 1, p5 present as mac on Th. II, m5i present
as mac on Th. II, 5+5 mac on Abd. I (a3) as mes, 4+4 central mac on Abd. II (a2 as
mac), 5+5 lateral mac on Abd. IV (F1 as mac).

Acknowledgments

Thanks are given to Dr. Feng Zhang (NJAU), who provided the material and facilities
when we visited his lab in August, 2015.Thanks should be given to Mr. Morgan A.
McClure, who helped to check the English text. The present study was supported by
the National Natural Sciences Foundation of China (41571247) and High Level Uni-
versity Construction Project of Guangdong Province (Regional Water Environment
Safety and Water Ecological Protection).

10 Guo-Liang Xu & Wei-Yu Chen / ZooKeys 611: I-10 (2016)

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